Linear motion guide with a positively guided cage for rolling elements

ABSTRACT

A linear motion guide for mounting and longitudinally guiding machine parts, in which a first guide element provided to be fixed to a machine part is guided by a plurality of rolling elements along a longitudinal movement axis with respect to a second guide element, likewise provided to be fixed to a machine part, for this purpose each guide element has a groove-like recess running parallel to the longitudinal movement axis, boundary surfaces of the recess in each guide element are provided as rolling surfaces for the rolling elements, the rolling elements are arranged one after another in one or more rows in at least one cage between the two guide elements, the cage is provided with at least one first positive guide, the cage with its first positive guide being guided by second positive guide fixed to the guide elements, each second positive guide being arranged only on one of the guide elements and being fixed in position relative to the latter. In order to provide this type of linear motion guide with accurate guidance and favourable fabrication and assembly properties, it is proposed that the second positive guide is fixed to the respective guide element ( 1, 2 ) outside the groove-like recesses ( 4, 5 ) and project between the two guide elements in order to guide the first positive guide and here are operatively connected to the first positive guide.

BACKGROUND OF THE INVENTION

The invention relates to a linear motion guide for mounting andlongitudinally guiding machine parts, in which a first guide elementprovided to be fixed to a machine part is guided by a plurality ofrolling elements along a longitudinal movement axis with respect to asecond guide element, likewise provided to be fixed to a machine part,for this purpose each guide element has a groove-like recess runningparallel to the longitudinal movement axis, boundary surfaces of therecess in each guide element are provided as rolling surfaces for therolling elements, the rolling elements are arranged one after another inone or more rows in at least one cage between the two guide elements,the cage is provided with at least one first positive guide means, thecage with its first positive guide means being guided by second positiveguide means fixed to the guide elements, each second positive guidemeans being arranged only on one of the guide elements and being fixedin position relative to the latter.

Linear motion guides of the generic type thus have at least one row ofrolling elements, which roll in the grooves, always in a rectilinearmovement. As distinct from recirculating linear motion guides, in thecase of generic linear motion guides the rolling elements do not leavetheir rectilinear movement path, in which they are in contact with bothguide elements in a load-bearing function. Linear motion guides of theabove-described type are usually provided in order to permit relativemovements of machine components.

In order that the rolling elements are always arranged at predetermineddistances from one another, it has been known for a long time to arrangethe rolling elements in a cage, as it is known. In a cage, a dedicatedmount is provided for each rolling element, in which the rolling elementcan move in rotation. The linearly moving guide element produces arotational movement in the rolling elements, from which a linearmovement of the rolling elements also results, by means of which in turnthe cage is carried along in a linear movement.

Intrinsically, the position of the cage and of the rolling elements withrespect to the two guide elements is always predetermined. However,because of external influences, displacement of rolling elements withrespect to their predetermined intended position may result. This canlead to a displacement of the cage, which in turn results in a change inthe displacement range in which the two guide elements, or the machinecomponents connected to the latter, can be displaced with respect to oneanother. In order to avoid such a movement, normally referred to as“cage wandering”, there already exist various forms of positive guidesfor the cage.

For example, in a first previously disclosed positive guide, provisionis made to connect a cage to a pinion. The pinion is located outside thetwo grooves, beside the two guide elements. The pinion engages in tworacks, which are each fixed to one of the two machine parts which areintended to execute the relative movements. The unsatisfactory aspect ofthis solution is that, because of the required fixing of the racks tothe machine parts, the manufacturer of the linear motion guide cannotsupply the latter in preadjusted form. The racks have to be fitted bythe machine manufacturer himself, and the individual guide componentshave to be toleranced relatively closely in order that the toothingsystem can function.

The same problem arises in the solution shown in U.S. Pat. No.4,524,671. In this document, a linear guide based on rolling-contactbearings for a gun barrel with respect to a guide sleeve is shown. Tothis end, so-called strips are formed on the gun barrel and bearingrails are formed on the guide sleeve. The rolling elements are arrangedin a cage in a spacing area between a strip and a bearing rail in eachcase. Furthermore, in order to guide the gun positively, in each case arack, in which a pinion arranged on the cage engages, is fixed to thestrip and the bearing rails. Both the pinion and the racks are locatedoutside the spacing area provided for the rolling elements for one ofthe strips with respect to one of the bearing rails.

In another solution, previously disclosed, inter alia, by U.S. Pat. No.5,427,454, in each case a rack is introduced into both guide elements,in the bottom of their grooves. A pinion connected to the cage ispositively guided by both racks. In this case, it can be felt to bedisadvantageous that the guide elements necessitate high fabricationexpenditure, because of the racks to be introduced. In addition, theassembly of the guide proves to be difficult, since the position of thecage can no longer be changed as soon as the pinion engages in theracks. A further difficulty consists in the mutual alignment of the tworacks arranged in the grooves, so that both racks engage correctly inthe pinion. In addition, there is the risk of damaging teeth duringassembly.

Finally, a further guide has been disclosed in which a cage belonging tothe rolling elements is positively guided. Here, in each case adeflection roller is fitted at the two ends of the cage, in which rollera thin rope or a string is guided in each case. The ends of the tworopes are in each case fixed to the ends of the guide elements. Thissolution also entails complicated assembly. In addition, the requiredthin strings and the small deflection rollers are susceptible todefects. It has also been shown that, on account of external influences,such as temperature changes, length changes of the strings can occur.The length changes lead to play of the cage or even to distortions ofthe cage between the two strings. If the cage is guided by resilientspring elements instead of by strings, as shown in U.S. Pat. No.4,262,974, then exact positive guidance can barely be achieved.

SUMMARY OF THE INVENTION

The invention is therefore based on the object of providing a linearmotion guide which, with the most accurate guidance possible of thecage, exhibits favourable fabrication and assembly properties.

In the case of a device of the type mentioned at the beginning, thisobject is achieved, according to the invention, by the second positiveguide means being fixed to the respective guide element outside thegroove-like recesses, projecting between the two guide elements in orderto guide the first positive guide means and here being operativelyconnected to the first positive guide means.

In a linear motion guide according to the invention, all the positiveguide means can already be brought by the manufacturer into serviceableoperative connection with one another, since all the positive guidemeans are fitted to the linear motion guide itself. This also results inno further components of the linear motion guide having to be fitted tothe machine parts, apart from the guide elements themselves. Since thesecond positive guide means are fixed to external surfaces, such as sidesurfaces, of the guide elements, which side surfaces are easilyaccessible, preferably even in the assembled state of the linear motionguide, linear motion guides according to the invention are alsocomparatively simple to assemble. Of course, it would also be possibleto fit each of the second positive guide means to an outer surface,located outside the groove, of one of the guide elements, the saidsurface lying opposite an outer surface of the other guide element inthe assembled state of the linear motion guide. Expressed in otherwords, the second positive guide means could also be fixed to surfacesof the guide elements which bound a gap between the two guide elements.

An additional advantage is that, in order to form a linear motion guideaccording to the invention, use can be made of conventional guideelements which are relatively simple to fabricate. These guide elementsmerely have to be modified to the effect that fixing the second positiveguide means to them is possible.

In the case of linear guides according to the invention, the secondpositive guide means should be fixed to their guide element in a fixedlocation, that is to say substantially immovably in relation to thesecond positive guide means. Immovable components can be assembled withcomparatively little effort and are in addition little susceptible todefects in operation.

In the case of linear guides according to the invention, the positiveguide means of the guide elements can preferably be intrinsically rigid,in order also to be able to absorb or to transmit loadings other thanonly pure tensile loadings, as is the case in the ropes previouslyknown. The property “intrinsically rigid” is therefore to be understoodas the opposite of the flexible ropes. In order to avoid damage to thepositive guide means, it may be advantageous if these have a certainelasticity, in spite of their rigidity, in order to be able to absorbloadings by means of reversible deformation. As a result of theelasticity, premature fracture of the component can be avoided. Thepositive guide means can therefore advantageously be configured from anappropriate metallic material or from plastic.

In preferred embodiments according to the invention, the second positiveguide means of the linear motion guides can each have an operativeconnecting part, which is operatively connected to the first positiveguide means, the operative connecting part arranged in a fixed locationon the guide element having a longitudinal extent which runs parallel tothe longitudinal movement axis.

In this case, a maximum length of the two operative connecting parts inthe displacement direction can correspond approximately to half, orslightly more than half, of the maximum displacement travel along whichthe two guide elements can be displaced in relation to each other. Inthe case of linear guides of the generic type based on rolling-contactelements, the cage always covers half the displacement travel executedby the two guide elements as a relative movement in relation to eachother. If the length of the operative connecting parts is chosen to beslightly greater than half the displacement travel, a secure operativeconnection between the positive guide means can be ensured even at theend of the displacement travel.

In a preferred embodiment, the first positive guide means is a pinionfixed to the cage such that it can rotate about an axis of rotation. Thepinion is preferably located in the centre of the cage. In particularwhen high forces act on the cage, a plurality of pinions can also beprovided. If the positive guidance is based on the engagement oftoothing systems, then the second guide means may be two racks, of whichin each case one is fitted to one of the guide elements. This embodimentoffers the advantage of high functional reliability of positive guidesbased on pinion/racks, without entailing the disadvantage of difficultassembly or of damaging teeth during the assembly.

In this case, it is further preferred for the racks to be designed as anangled profile in relation to a cross section, it being possible for thesaid profile to have a fixing leg and a toothed leg angled with respectthereto. The fixing leg is advantageously fitted to a freely accessibleside surface of the corresponding guide element, running parallel to thelongitudinal movement axis. The toothed leg provided as operativeconnecting part of the second positive guide means can engage in a gapbetween the two guide elements and can be operatively connected there tothe second positive guide means.

If the racks on outer surfaces of the guide elements are in each casefitted to different sides of the two guide elements, then the two guideelements, including the fixing means required on the guide elements, canbe configured to be completely structurally identical. This reduces theoutlay on fabrication.

Although a positive guide based on tooth engagements is preferredaccording to the invention, instead of this, however, other form-fittingor else force-fitting positive guides can also be provided, such aspositive guides using magnetic or inductive forces.

Further preferred refinements of the invention emerge from the claimsand the drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail using an exemplaryembodiment illustrated purely schematically in the figures, in which:

FIG. 1 shows a sectional illustration of an embodiment according to theinvention based on balls as rolling-contact elements;

FIG. 2 shows a sectional illustration of the linear guide of FIG. 1along the line II—II;

FIG. 3 shows a guide element with inserted cage belonging to a linearmotion guide according to the invention and based on rollers;

FIG. 4 shows a sectional illustration of a further exemplary embodimentaccording to the invention;

FIG. 5 shows a front view of a rack from FIG. 4;

FIG. 6 shows an illustration of a cross section of the exemplaryembodiment of FIG. 4 in the vicinity of one end of the guide elements;

FIG. 7 shows a side view of one of the guide elements from FIG. 6;

FIG. 8 shows an illustration according to the line VIII—VIII from FIG.7.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 and 2 show a linear motion guide according to the invention,which has two guide elements 1, 2 designed as profile strips. Thedirection of the longitudinal extent of the two guide elements 1, 2corresponds to a longitudinal movement axis 3, along which a relativemovement between the two guide elements is possible. A single V-shapedgroove 4, 5 is made in each of the guide elements 1, 2, which have arectangular cross section. The two grooves 4, 5 lie with their opensides opposite and, in cross section, are designed as equilateraltriangles with an opening angle of 90° in each case. Boundary surfaces 4a, 4 b, 5 a, 5 b of the two grooves 4, 5 function as rolling surfacesfor rolling elements. The grooves 4, 5 each extend over the entirelength of their guide elements 1, 2. As will be explained in more detailbelow, a structural unit, which has a cage and rolling elements arrangedtherein and a first positive guide means designed as a pinion, islocated in the grooves 4, 5. By means of this structural unit, relativemovements between the two guide elements are possible. The structuralunit will be described in more detail below.

In each case on an outside side surface 6, 7 of each guide element,running parallel to the longitudinal movement axis, a second positiveguide means in the form of a rack 8, 9 is fixed by means of a pluralityof screws, not shown. Of course, other types of fixing, such as snap-inconnections, are also possible. The racks 8, 9, just like the pinion,are made of a metallic material or plastic and, on the basis of anappropriate material selection and adequate dimensioning, are designedto be intrinsically rigid. As can be seen in both figures, the racks 8,9 are fixed to the guide elements 1, 2 on respectively different sidesof the linear motion guide. A maximum length in the displacementdirection of the two racks corresponds to about half, or slightly morethan half, of the maximum displacement travel along which the two guideelements can be displaced with respect to each other.

In the embodiment shown in the figures, the rolling elements aredesigned as balls 10. All the balls 10 are arranged one behind anotherin only one row at right angles to the plane of the drawing of FIG. 2.The balls 10 rest on the two rolling surfaces 4 a, 4 b; 5 a, 5 b of eachgroove 4, 5 and transmit the load from the machine part (not shown)connected to the moveable guide element 1 to the fixed-position guideelement 2, for example connected to a machine frame. In each casesuccessive balls 10 are arranged at the same distance from one anotherin holders in the cage 11. In this case, the balls 10 are located withlittle play in their holders, so that they can rotate freely in theirholders.

The cross-sectional illustration of FIG. 2 runs exactly through an axisof rotation 16 of the pinion 15, which can preferably be located in thecentre of the cage 11 (in relation to the longitudinal extent). As FIG.2 reveals, the disc-like pinion 15, illustrated very schematically,arranged with a rotational shaft 14 on the cage 11 is also located inthe centre of the cage 11 in a direction transverse with respect to thelongitudinal movement axis. The rotational shaft 14 forms the axis ofrotation 16 of the pinion 15. This shaft is aligned at right angles tothe longitudinal movement axis 3 and at right angles to outer contactsurfaces 1 a, 2 a of the guide elements 1, 2, on which machine partsrest on the guide elements. As a result of this alignment of the pinion15, the longitudinal movement axis runs through a circumferentialsurface of the pinion 15, on which a toothing system 15 a is formed.

The pinion 15 is continuously engaged with toothing systems 17 (cf.FIG. 1) of toothed legs 18, 19 of each rack 8, 9. The toothing systems17 are designed as rectilinear toothing systems on the free ends of twotoothed legs 18, 19. The toothed legs 18, 19 are in turn provided aslegs of one of the two racks 8, 9 in each case. The two toothed legs 18,19 engage from different sides in a gap 20 (FIG. 2), which is formedbetween the two guide elements 1, 2. A fixing leg 21, 22, bent over at aright angle in relation to the toothed leg 18, 19 of each rack 8, 9, isin each case fitted to the outer side surface 6, 7 of the guide elements1, 2. As FIG. 2 shows, the fixing leg 21 of the rack 8 of the movableguide element 1 is fitted to its right-hand outer side surface 6. Thefixing leg 22 of the rack 9 of the fixed-position guide element 2 is, onthe other hand, fixed to its left-hand outer side surface 7.

From this, it can be seen that both the two guide elements 1, 2 and thetwo racks 8, 9 can be configured identically in relation to therespective cross sections, which reduces the outlay on fabricationconsiderably. The two guide elements 1, 2 and the two racks 8, 9,respectively, can differ from one another only in terms of their length,which has no influence on the fabrication expenditure, but at most onlya very low influence.

During a linear movement of the upper guide element 1, which can beproduced by means of a drive to the machine part connected to the upperguide element 1, the guide element 1 with the rolling surfaces 4 a, 4 bmoves on the balls 10. Here, the balls 10 are carried along by means ofa frictional connection with the rolling surfaces 4 a, 4 b and rotate.The length of the longitudinal movement of the centre of each ball 10 isin this case half the length of the longitudinal movement of the upperguide element 1. The balls 10 in turn take the cage 11 along with themduring their movement, the said cage moving linearly by the same lengthas the centres of the balls. By this means, the pinion 15 is also setrotating about the axis of rotation 16. At the same time, the pinion 15engages in the toothing systems of the two racks 8, 9. Because of theoperative connection between the pinion 15 and the two racks 8, 9, thecage 11 is guided positively and its position during a specificlongitudinal movement of the guide element 1 is predetermined.

A further exemplary embodiment according to the invention is shown inFIG. 3. For better clarity, of the two guide elements only the lowerguide element 2 is shown, in whose groove the cage 11 is inserted. Thiscage 11, too, accommodates rolling elements and a pinion 15 in recesses.This exemplary embodiment differs from the exemplary embodiment shown inFIG. 1 substantially only in terms of other rolling elements and theirarrangement. For this reason, only this difference will be discussedbelow. Firstly, in FIG. 3 rollers 110 are used instead of balls.Secondly, the rollers 110 are arranged in two rows 111, 112 runningparallel to each other and parallel to the longitudinal movement axis.Rollers 110 of the same row 111, 112 are distinguished by the fact thatin each of the two grooves 5 in the two guide elements, they rest on thesame but only on one of the rolling surfaces 5 a, 5 b. Thus, in FIG. 3,rollers 110 of the row 111 rest on the rolling surface 5 b, while therollers 110 of the row 112 are supported on the rolling surface 5 a. Inthe exemplary embodiment of FIG. 3, the rollers of the two rollers 111,112 are arranged offset from one another in the longitudinal movementdirection 3. Such an alternating arrangement of rolling elements in thelongitudinal movement direction is also referred to as crossed-rollerguidance.

FIG. 4 shows preferred fixing of two positive guide means, in particularof a rack 8, 9, to the respective guide elements 1, 2. Such a rack 8 isshown in more detail in FIG. 5. As can be gathered from FIG. 4, on theirouter side surfaces 6, 7, on which in each case a fastening leg 21, 22of a rack 8, 9 comes to rest, the guide elements 1, 2 each have at leastone groove-like recess 24, 25, whose longitudinal extent runs parallelto the longitudinal movement axis. Each guide element 1, 2 is furtherprovided with a further groove 28, 29 running parallel to thelongitudinal movement axis in each case on a further surface 26, 27,which is located in the gap 20 and opposite a toothed leg 18, 19.

Each rack 8, 9 of this embodiment can have, on their fixing legs 18, 19,at least two elongated webs 30, 31 which are aligned parallel to thelongitudinal movement axis and which are provided to engage in one ofthe grooves 24, 25. The height of the webs 30, 31 should thus beslightly less than the depth of the grooves 24, 25. In addition, eachtoothed leg 18, 19 has, on a plurality of teeth 17 a, projections 32beyond the respective tooth width. Since the projections 32 are providedin order to engage in one of the grooves 28, 29, here, too, the heightof the projections 30, 31 should be matched to the groove depth and, ifnecessary, to a distance between the respective toothed leg 18, 19 andthe respective surface 26, 27.

In order to fix the racks 8, 9 of this embodiment, provision can be madeto slide the racks 8, 9 along into the grooves 24, 25, 28, 29 from oneend of a guide element 1, 2 with the webs 30, 31 and projections 32. Theracks 1, 2, preferably consisting of plastic, can then be fixed by meansof plates (not illustrated) screwed onto the guide elements 1, 2 at theends and resting against the rack. For this purpose, the racks 8, 9should be as long as the guide elements. In order that the racks 8, 9are fixed without play, even in directions transverse with respect tothe longitudinal movement axis, the webs 30, 31 and projections 32should preferably rest against those groove surfaces 28 a, 29 a whichare closest to the chamfered corners 34, 35 of the guide elements.

Provision can also be made to fix the second guide means, in particularthe racks 8, 9, to the guide element without further fixing means, onlyby means of a form fit and/or force fit between the respective guideelement 1, 2 and the guide means. For this purpose, for example,provision can be made to match the dimensions of the grooves 24, 25, 28,29 to the dimensions of the webs 30, 31 and projections 32 in such a waythat the webs 30, 31 and projections 32 each rest against the groovesurfaces 28 a, 29 a lying closer to the corners 34, 35 with anadequately high clamping force. In order to mount one of the twopreferably identical racks on the respective guide element, it may benecessary here to widen somewhat the angle formed by the two legs 18,21; 19, 22 of the respective rack 8, 9. The restoring forces of the legswhich are produced in this way can be used to produce a form fit indirections transverse to the longitudinal movement axis, and a force fitin a direction parallel to the longitudinal movement axis, by means ofthis snap-in connection between the guide element and the respectiverack. In order to assemble a rack on a guide element, the rack caneither be clipped on or pushed on at the end.

In FIGS. 6, 7 and 8, one possible way of locking the second guide means(not reproduced in these illustrations) in the direction of thelongitudinal movement axis 3 is shown. To this end, in each case a stoppart 40 which is approximately rectangular in cross section andrelatively short in the direction of the longitudinal movement axis 3 isfixed to one of the side surfaces 6, 7 of the guide element 1, 2, in thearea of each end of the guide element 1, 2, and in the respective twogrooves 25, 29. Any possible slight movement, which may be present, ofthe corresponding second guide means in the direction of thelongitudinal movement axis 3 is limited by striking against the two stopparts 40 of each guide element.

On a section opposite the side surface 6, 7 of the respective guideelement, each stop part 40 has two spring legs 41, 42, which engage in ahorizontal hole 43 in the guide element 2. The spring legs 41, 42 arelocated substantially on a line 44 which runs parallel to thelongitudinal movement axis 3. They rest against the wall 43 a of thehole, producing a spring force, and secure the stop part 40 againstdisplacement in a direction parallel to the longitudinal movement axis3. In addition, the stop part 40 also has a web 30 and a projection 32,which engage in the grooves 25, 29 in the guide element 2. By means ofthe clamping force also produced by this web 30 and projection 32, thestop part 40 is fixed in directions transverse to the longitudinalmovement axis 3.

What is claimed is:
 1. Linear motion guide for mounting andlongitudinally guiding machine parts, in which a first guide elementprovided to be fixed to a machine part is guided by a plurality ofrolling elements along a longitudinal movement axis with respect to asecond guide element, likewise provided to be fixed to a machine part,for this purpose each guide element has a groove-like recess runningparallel to the longitudinal movement axis, boundary surfaces of therecess in each guide element are provided as rolling surfaces for therolling elements, the rolling elements are arranged one after another inone or more rows in at least one cage between the two guide elements,the cage is provided with at least one first positive guide means, thecage with its first positive guide means being guided by second positiveguide means fixed to the guide elements, each second positive guidemeans being arranged only on one of the guide elements and being fixedin position relative to the latter, wherein the second positive guidemeans are fixed to the respective guide element outside the groove-likerecesses on an outer surface of the respective guide element and projectbetween the two guide elements in order to guide the first positiveguide means and here are operatively connected to the first positiveguide means in a form-fitting engagement.
 2. Linear motion guideaccording to claim 1, wherein at least one of the guide elements has asubstantially rectangular cross section, there being a V-groove as arecess in the area of one surface of the respective guide element. 3.Linear motion guide according to claim 1, wherein each of the secondpositive guide means is fitted to a side surface of a guide element. 4.Linear motion guide according to claim 3, wherein the side surface runssubstantially parallel to the longitudinal movement axis.
 5. Linearmotion guide according to claim 1, wherein at least one of said guidemeans is fixed to one of the guide elements by means of a snap-inconnection.
 6. Linear motion guide according to claim 1, wherein secondpositive guide means of different guide elements are arranged onrespectively different sides of the two guide elements.
 7. Linear motionguide according to claim 1, wherein the second positive guide means eachhave an operative connecting part that is operatively connected to thefirst positive guide means, the operative connecting part having alongitudinal extent which runs parallel to the longitudinal movementaxis.
 8. Linear motion guide according to claim 7, wherein the operativeconnecting part of at least one of the second positive guide means isdesigned as a rack.
 9. Linear motion guide according to claim 8, whereinthe racks are each designed as an angled profile having a fixing leg anda toothed leg that is angled over with respect to the fixing leg, thefixing leg resting on a side surface of the guide element and thetoothed leg projecting into a gap between the two guide elements. 10.Linear motion guide according to claim 8, wherein the length of theracks substantially corresponds to half the maximum displacement lengthalong which the two guide elements can be displaced relative to eachother.
 11. Linear motion guide according to claim 8, wherein said firstpositive guide means is a pinion, is disposed on said cage and isoperatively connected to the racks.
 12. Linear motion guide according toclaim 11, wherein the pinion has an axis of rotation which is aligned atright angles to the longitudinal movement axis and which intersects bothguide elements.
 13. Linear motion guide according to claim 11, whereinin relation to the longitudinal movement direction, the pinion isarranged approximately in the centre of the cage.
 14. Linear motionguide for mounting and longitudinally guiding machine parts, in which afirst guide element provided to be fixed to a machine part is guided bya plurality of rolling elements along a longitudinal movement axis withrespect to a second guide element, likewise provided to be fixed to amachine part, for this purpose each guide element has a groove-likerecess running parallel to the longitudinal movement axis, boundarysurfaces of the recess in each guide element are provided as rollingsurfaces for the rolling elements, the rolling elements are arranged oneafter another in one or more rows in at least one cage between the twoguide elements, the cage is provided with at least one first positiveguide means, the cage with its first positive guide means being guidedby second positive guide means fixed to the guide elements, each secondpositive guide means being arranged only on one of the guide elementsand being fixed in position relative to the latter; and wherein thesecond positive guide means are fixed to the respective guide elementoutside the groove-like recesses and project between the two guideelements in order to guide the first positive guide means and here areoperatively connected to the first positive guide means of said means ofa snap-in connection; and at least one of said guide means is fixed toone of the guide elements by a snap-in connection.
 15. Linear motionguide according to claim 14, wherein at least one of the two secondpositive guide means is fixed to at least one outer surface of the guideelements.
 16. Linear motion guide for mounting and longitudinallyguiding machine parts, in which a first guide element provided to befixed to a machine part is guided by a plurality of rolling elementsalong a longitudinal movement axis with respect to a second guideelement, likewise provided to be fixed to a machine part, for thispurpose each guide element has a groove-like recess running parallel tothe longitudinal movement axis, boundary surfaces of the recess in eachguide element are provided as rolling surfaces for the rolling elements,the rolling elements are arranged one after another in one or more rowsin at least one cage between the two guide elements, the cage isprovided with at least one first positive guide means, the cage with itsfirst positive guide means being guided by second positive guide meansfixed to the guide elements, each second positive guide means beingarranged only on one of the guide elements and being fixed in positionrelative to the latter; and wherein the second positive guide means arefixed to the respective guide element outside the groove-like recessesand project between the two guide elements in order to guide the firstpositive guide means and here are operatively connected to the firstpositive guide means; the second positive guide means each have anoperative connecting part that is operatively connected to the firstpositive guide means, with the operative connecting part having alongitudinal extent which runs parallel to the longitudinal movementaxis; each operative connecting part is a rack; and the racks are eachdesigned as an angled profile having a fixing leg and a toothed leg thatis angled over with respect to the fixing leg, with the fixing legresting on a side surface of the guide element, and the toothed legprojecting into a gap between the two guide elements.